1. Field of the Invention
The present invention relates to a cylinder head for a multi-cylinder direct-injection spark-ignition internal combustion engine.
Various types of conventional cylinder heads have been developed in the past in order to achieve the best mixture preparation possible in internal combustion engines. In addition to the requirements of the mixture preparation, further demands such as low weight, high cooling capacity and ease of assembly are being made. This applies in particular to cylinder heads of high-performance engines.
2. Summary of the Invention
It is accordingly an object of the invention to provide a cylinder head for a multi-cylinder direct-injection spark-ignition internal combustion engine which is distinguished by a good mixture preparation, low weight and great ease of assembly and is therefore also suitable for high-performance engines.
With the foregoing and other objects in view there is provided, in accordance with the invention, a cylinder head for a direct-injection spark-ignition internal combustion engine with a plurality of cylinders, the cylinder head including:
an inlet valve provided for each of a plurality of cylinders;
an exhaust valve provided for each of the plurality of cylinders;
a first receptacle provided for each of the plurality of cylinders, the first receptacle being configured to receive an ignition device or an injection device, and the first receptacle being disposed substantially parallel to the inlet valve;
a second receptacle for each of the plurality of cylinders, the second receptacle being configured to receive an ignition device or an injection device, and the second receptacle being disposed substantially parallel to the exhaust valve;
a third receptacle provided for each of the plurality of cylinders, the third receptacle being configured to receive an ignition device or an injection device;
a first valve actuating element for actuating the inlet valve;
a second valve actuating element for actuating the exhaust valve, the first valve actuating element and the second valve actuating element being constructed substantially identically; and
a common camshaft for actuating the inlet valve and the exhaust valve via the first valve actuating element and the second valve actuating element, the common camshaft being disposed offset from a cylinder center plane defined by the plurality of cylinders.
In other words, the object of the invention is achieved by a cylinder head which has, per cylinder, an inlet valve, an exhaust valve, a first receptacle and a second receptacle for respective ignition devices, for an ignition device and an injection device or for respective injection devices, and a third receptacle for an injection device or an ignition device, the inlet valve and the exhaust valve being actuated via valve-actuating elements of identical configuration by a common camshaft disposed offset from the center plane of the cylinder, and the first receptacle being disposed essentially parallel to the inlet valve and the second receptacle being disposed essentially parallel to the exhaust valve. Thus, according to the invention, a cylinder head for an internal combustion engine is provided, that allows twin ignition or twin injection due to its three receptacles for two ignition devices and one injection device or for two injection devices and one ignition device. This ensures an optimized ignition and respectively an optimized movement of the charge and thus an improved mixture preparation. Moreover, the cylinder head according to the invention is a weight-saving and compact configuration since it has just two engine valves per cylinder and a common camshaft for the engine valves. Due to the fact that the valve-actuating elements are constructed as identical parts, this cylinder head is furthermore very easy to assemble because there is no risk of a mix-up. And, due to the offsetting of the camshaft, it is, according to the invention, equally easy to work on the inlet side and on the exhaust side of the cylinder head despite the difference in the size of the engine valves.
According to another feature of the invention, the third receptacle is provided for the injection device and advantageously opens into the cylinder in a position laterally adjacent to the inlet valve and to the first receptacle which is provided for the ignition device. The injection device is thus inclined with respect to the inlet valve and the first receptacle for the ignition device and preferably has a spray cone having an angle of about 70 degrees and being inclined at an angle of about 58 degrees with respect to the horizontal and about 15 degrees with respect to the vertical. Other angles are, of course, also possible.
According to a first alternative feature of the invention, the valve-actuating elements are constructed as cam follower levers, which are mounted on a cam follower shaft which is provided below and parallel to the camshaft. As a result, only a small amount of installation space within the cylinder head is required for the cam follower levers, and the cylinder head can be built as an extremely flat construction.
According to a second alternative feature of the invention, the valve-actuating elements are embodied as rocker levers or rockers, which are mounted on two rocker shafts disposed above and parallel to the camshaft. As a result, the rocker space within the cylinder head is easily accessible and therefore configured in such a way as to make assembly very easy.
With the objects of the invention in view there is also provided, in combination with a direct-injection spark-ignition internal combustion engine including cylinders with respective cylinder axes disposed in a cylinder center plane, a cylinder head including an inlet valve per cylinder; an exhaust valve per cylinder; a first receptacle per cylinder, the first receptacle being disposed substantially parallel to the inlet valve; a second receptacle per cylinder, the second receptacle extending substantially parallel to the exhaust valve; a third receptacle per cylinder, the first, second and third receptacles being configured to receive an ignition device or an injection device; a first valve actuating element for actuating the inlet valve; a second valve actuating element for actuating the exhaust valve, the first valve actuating element and the second valve actuating element being constructed substantially identically; and a common camshaft for actuating the inlet valve and the exhaust valve via the first valve actuating element and the second valve actuating element, the common camshaft having a longitudinal axis extending parallel to the cylinder center plane and being spaced from the cylinder center plane by a given spacing distance.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a cylinder head for a multi-cylinder direct-injection spark-ignition internal combustion engine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.